The present invention is directed to a robot end effector for performing post-molding operations on articles such as vehicle bumper fascias. More particularly, the present invention is directed to a single robot end effector that is capable of both trimming and flame treating such articles.
It would be well understood by one skilled in the art that molds for making plastic parts such as bumper fascias typically include one or more gates through which molten plastic material is injected during the molding process. Plastic mold gates can be of various design. A gate design commonly employed in larger parts such as bumper fascias is a film or ribbon gate design, wherein a long, thin gate, is located along an edge of the part.
For aesthetic and/or other reasons, molding gates must typically be removed from molded parts after molding. Gate removal is commonly accomplished, at least with softer plastic materials such as those used in bumper fascia manufacturing, by trimming with a knife. While the gate trimming process may be performed manually, the use of automated or robotic gate trimming devices is becoming more common.
In addition to gate removal, plastic parts such as bumper fascias often require the removal of flash, which typically occurs along a parting line between mold halves or between a mold half and a mold core. When the location of flash on a part will be visible, such as may be the case once a bumper fascia is installed to a vehicle, it must be ensured that the appearance of the flashed area is acceptable. Even when flash is not an issue, parting lines themselves may also present an unacceptable appearance—especially after receiving paint.
Further, when applicable such as in the case of bumper fascias, it must be ensured that the material of which the part is constructed will exhibit proper paint adhesion. As would be understood by one of skill in the art, the nature of some plastic materials, particularly the thermoplastic polyolefins such as the polypropylene blends commonly used to mold bumper fascias, can render it difficult to impart an acceptable appearance. The presence of flash and/or an unacceptable parting line may exacerbate such adhesion resistance to primers and/or paint adhesion.
Consequently, various processes have been developed to alleviate these problems. One such process is localized flame treatment. In a localized flame treatment process, a flame is passed over an area of previously trimmed flash, or may be used to remove areas of light flash in lieu of removal thereof with a knife or other trimming device. It may also be possible to enhance the appearance and/or adhesion to paint of a previously trimmed area of a molded part, such as a gate removal area.
Flame treatment may be accomplished manually or through use of automated equipment, such as a robot. In either case, known systems and methods have typically required the use of separate trimming and flame treatment devices. For example, in a manual operation, an operator is generally required to use a knife or similar device when trimming a gate and/or flash. Once trimming is complete, the operator is then required to put down the trimming device and pickup a flame treatment device, such as a portable torch. A similar requirement applies to automated or robotic flame treatment systems and methods wherein, for example, a robot is required to switch between trimming and flame treatment end-of-arm tooling (end effector) when switching between process steps.
While switching between trimming and flame treatment devices may not seem burdensome when considered over one or a small number of trimming/flame treatment processes, it can be easily understood how such a requirement is burdensome and time consuming when considered over hundreds of thousands of such processes. Therefore, it would be desirable to eliminate the need to switch between separate trimming and flame treatment devices when performing such aforementioned post-molding processes. The present invention is directed to a combination trimming/flame treatment device for use by a robot, which device and method of use eliminates the need to switch between separate trimming and flame treatment devices.